I suspect that the banks in Bangkok recently issued an internal directive not to open bank accounts on the basis of a tourist visa.
Since dozens of tourists still come every day and want to open a bank account with a tourist visa, the bank employees are getting increasingly annoyed.
The fact that so many people still want to open a bank account in Bangkok with a tourist visa is also because in Facebook groups like this one, many people still claim that it is easy to open a bank account in Bangkok with a tourist visa.